This patch adds release callback support, which is called when a bsg
device goes away. bsg_register_queue() takes a pointer to a callback
function. This feature is useful for stuff like sas_host that can't
use the release callback in struct device.

If a caller doesn't need bsg's release callback, it can call
bsg_register_queue() with NULL pointer (e.g. scsi devices can use
release callback in struct device so they don't need bsg's callback).

With this patch, bsg uses kref for refcounts on bsg devices instead of
get/put_device in fops->open/release. bsg calls put_device and the
caller's release callback (if it was registered) in kref_put's
release.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

It's big, but there doesn't seem to be a way to split it up smaller...

Signed-off-by: Tony Jones <tonyj@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

This updates sg_io_v4 structure (based on Doug's RFC, release 1.3).

The major changes are:

- add dout_resid field
- increase tag size to 64 bits to comply with SAM-4 and SRP
- add dout_iovec_count and din_iovec_count

dout_iovec_count and din_iovec_count aren't supported now. I'm not
sure whether they will be supported or not but they were added for the
possible future changes.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

Just using #defines for the
bsg_register_queue()/bsg_unregister_queue() can cause undefined
variables when they're defined to nothing.  Use dummy inline functions
instead.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

This replaces the current linear search for a unique minor number with
lib/idr.c.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

Currently, bsg doesn't make class backlinks (a process whereby you'd get
a link to bsg in the device directory in the same way you get one for
sg).  This is because the bsg device is uninitialised, so the class
device has nothing it can attach to.  The fix is to make the bsg device
point to the cdevice of the entity creating the bsg, necessitating
changing the bsg_register_queue() prototype into a form that takes the
generic device.

Acked-by: FUJITA Tomonori <tomof@acm.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

Don't define an empty struct bsg_class_device if !CONFIG_BLK_DEV_BSG.

It's embedded in struct request_queue, but there we have

#if defined(CONFIG_BLK_DEV_BSG)
	struct bsg_class_device bsg_dev;
#endif

anyway.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This enables bsg to handle SCSI transport-level request like SAS
management protocol (SMP).

- add BSG_SUB_PROTOCOL_{SCSI_CMD, SCSI_TMF, SCSI_TRANSPORT} definitions.
- SCSI transport-level requests skip blk_verify_command().

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This fixes the following minor issues:

- add EXPORT_SYMBOL_GPL for bsg_register_queue and
bsg_unregister_queue.

- shut up gcc warnings

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <axboe@nelson.home.kernel.dk>

This patch binds bsg devices to request_queue instead of gendisk. Any
objects (like transport entities) can define own request_handler and
create own bsg device.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>